Syphilis symptoms unfold in stages. The first is usually a single painless sore (chancre) where the bacteria entered, about three weeks after exposure. Weeks later comes a rough rash, often on the palms and soles, plus flu-like signs. Symptoms then vanish on their own, but the infection stays unless it's treated.
| Item | Reported cases (babies) |
|---|---|
| 2020 | 2,163 |
| 2021 | 2,881 |
| 2022 | 3,769 |
| 2023 | 3,882 |
Syphilis is caused by the bacterium Treponema pallidum and spreads through direct contact with a syphilis sore during vaginal, anal, or oral sex, and from a pregnant person to the baby CDC. It's caught late because each stage's symptoms fade whether or not you're treated, so the body feels like it's recovering while the bacteria move deeper. Below is what each stage looks and feels like, and why a healed sore doesn't mean you're in the clear.
Primary stage: the painless chancre
The first sign is a chancre, one or more firm, round, painless sores at the exact spot the bacteria got in. That means the penis, vagina, anus, rectum, lips, or mouth. A chancre lasts roughly three to six weeks and heals on its own, with or without treatment.
A sore that doesn't hurt and sits somewhere you can't see, inside the vagina, in the rectum, at the back of the throat, is easy to never notice. And because it disappears by itself, the few people who do spot it often assume it was nothing and got better. Meanwhile the infection is moving inward. If you had a recent risk, a sore that quietly came and went is a reason to get tested.
Secondary stage: the rash on palms and soles
Weeks after the chancre heals, the bacteria spread through the bloodstream and the secondary stage begins. Look for a rough, red or reddish-brown rash that can show up on the palms of the hands and the soles of the feet, an unusual location that makes a clinician think of syphilis, and/or across the body. The rash usually doesn't itch, which throws people off.
Secondary syphilis often comes with a cluster of other signs: moist sores on mucous membranes, fever, swollen lymph nodes, sore throat, patchy hair loss, headache, weight loss, muscle aches, and deep fatigue. It can feel like a bad flu with a strange rash. As with the chancre, all of it resolves on its own, which is exactly why it gets missed.
Latent stage: the silent years
After secondary symptoms clear, syphilis goes underground into the latent stage. No symptoms at all, sometimes for years, while the bacteria persist in the body and remain detectable on a blood test CDC. Clinicians split this stage by how long ago you were infected. Early latent means acquired within the past year, shown by a documented recent test conversion, a fourfold or greater rise in titer, or recent primary or secondary signs. Anything longer ago, or unknown timing, is late latent or unknown duration.
That distinction sets the treatment schedule, and people in early latent infection can still pass syphilis to a partner or, during pregnancy, to a baby.
Tertiary, neuro, and ocular syphilis: what late untreated infection does
Left untreated for years, syphilis can progress to the tertiary stage, typically described as appearing 10 to 30 years after infection, though that's not a guaranteed symptom-free window. Tertiary syphilis damages the heart, blood vessels, brain, and nervous system, and it can be fatal.
Two complications deserve their own warning because they aren't only late events. Neurosyphilis (infection of the brain and spinal cord, which can cause confusion, headaches, paralysis, or dementia-like decline) and ocular syphilis (infection of the eye, which can cause vision loss or blindness) can occur at any stage of syphilis CDC. Otosyphilis affects hearing and balance. New vision changes, hearing loss, or neurological symptoms in someone with syphilis are a medical emergency, so go in the same day.
Why symptoms going away does NOT mean you're cured
This is the single most important thing to understand about syphilis. As the CDC puts it: the symptoms from each stage will go away whether or not you receive treatment, and without the right treatment your infection will move to the latent and possibly tertiary stages. A sore or rash disappearing is the natural course of the disease. Only antibiotics clear the bacteria, and only a follow-up blood test confirms it.
How soon do syphilis symptoms appear?
The primary chancre shows up about three weeks after exposure on average, with a possible range of roughly 10 to 90 days. Because that incubation is wide and the first sore is painless, the timeline is hard to track from symptoms alone, so testing on a sensible schedule matters more than waiting to feel something. See when to test after exposure for the right timing.
How syphilis is tested
Diagnosis is a simple blood draw, but it takes two serologic tests rather than one CDC, 2024. A nontreponemal test (RPR or VDRL) and a treponemal test (TP-PA, FTA-ABS, EIA, or CIA) are run together, one to screen and one to confirm, and labs may run them in either order (traditional or reverse-sequence). A single positive isn't enough on its own.
Timing trips people up. Very early, the blood may not yet show antibodies. They can take up to about two weeks after the chancre appears, and the chancre itself shows up around three weeks post-exposure. So a negative test soon after a known risk doesn't rule syphilis out; retest rather than trusting that result. For the full how-to, see syphilis testing.
Treatment: penicillin by stage
Syphilis is curable, and penicillin G given by injection is the preferred drug for every stage CDC. The dose follows the stage: early syphilis (primary, secondary, and early latent) takes a single intramuscular injection of benzathine penicillin G, while late latent, unknown-duration, and tertiary disease take three weekly injections. No oral pill reliably substitutes, and azithromycin is not recommended because of resistance.
The correct product is benzathine penicillin G (Bicillin L-A). The combination product Bicillin C-R is not an acceptable substitute and has caused treatment-failure errors. Neurosyphilis, ocular, and otosyphilis need a different, IV-based regimen entirely.
| Stage | Standard penicillin treatment |
|---|---|
| Primary, secondary, early latent (≤1 year) | A single benzathine penicillin G injection |
| Late latent / unknown duration / tertiary | Three weekly benzathine penicillin G injections |
| Neuro / ocular / otosyphilis (any stage) | IV aqueous crystalline penicillin G over 10–14 days |
You may get a flare in the first day after treatment: fever, chills, headache, and muscle aches within a couple of hours of the injection. This is the Jarisch-Herxheimer reaction, caused by dying bacteria releasing inflammatory signals, not a penicillin allergy StatPearls. It's common when treating early syphilis and settles within about a day. Knowing it's coming keeps you from mistaking it for a drug reaction.
Most reported penicillin allergy turns out to be mislabeled, which matters because penicillin is the only reliable cure. After treatment, cure is confirmed by blood rather than by feeling fine: repeat quantitative RPR/VDRL titers should show a fourfold or greater decline over the following months. Full details are in syphilis treatment.
When to see a clinician
See a clinician for any new painless sore on the genitals, anus, or mouth; any unexplained rash on the palms or soles; a flu-like illness after a sexual risk; or if a partner tests positive. Seek same-day care for new vision changes, hearing loss, or neurological symptoms. If you're pregnant, get screened. Congenital syphilis is rising sharply and is preventable with prenatal screening plus penicillin; see syphilis in pregnancy CDC.